Not too long from now, winter will be a distant memory, and home owners will worry about how to cool their houses and condominiums efficiently and cost effectively. But in the meantime, sellers who’ve sealed their houses tightly are coasting on easy street compared to those hurriedly trying to caulk drafty windows and doors or apply films over glazing before the next showing as temperatures plummet.

Making a house or condo snug for an owner as well as a future buyer is wise. They’ll enjoy their home more and cut heating and cooling costs.

However, many sellers aren’t sure where to invest insulation dollars, and some buyers coming to ownership from a rental aren’t aware of the need to inquire about insulation, says sales associate Stephanie Mallios with Towne Realty Group in Short Hills, N.J.

Smart choices can make the difference in closing faster and securing a higher offer, particularly in areas prone to hotter and colder temperatures. Your job also will be easier if you can tout good insulation in listing and marketing materials and demonstrate how they lower expenses.

Here are answers to seven key insulation questions that you can share with your buyers and sellers:

1. Where do home owners and buyers begin if they want to improve insulation or find out how insulated a home is?

They should start with an energy audit if it hasn’t been done — or at least done in a while — since the range of energy use among home owners can be very significant even when houses are similar, says Martha Amram, CEO and cofounder of Wattzon in Mountain View, Calif., which helps home owners save energy and money. The best person to hire is a contractor who’s certified through an organization like the Building Performance Institute. The contractor will go through a house from top to bottom, inside and out, to get information about its insulation — particularly whether it’s leaking heat or cold air and where. Tell your buyers and sellers to think of the audit as their home’s annual exam, says Scott Fischer, an accredited BPI contractor with Ciel Power in Lyndhurst, N.J. For an average-size house, work generally takes between three and four hours. Prices vary but typically run between $300 and $400 for an average-size home. Some states and municipalities provide free audits or software that can project the savings. Some also offer rebates when home owners purchase high-efficiency products. Check the U.S. Department of Energy’s national database of efficiency-related incentives for more information.

2.How is insulation rated?

By R values, which measures how well insulation resists heat — and cold — traveling through it. The higher the R value, the better its ability to keep homes warm in the winter and cool in the summer, respectively. Values vary by climate, so check the federal government’s map.

3.With information in hand, how do home owners or buyers proceed?

They should prioritize, since they rarely have unlimited funds to cover every insulation possibility. They should approach insulating their house the same way they follow a master plan to remodel or decorate their home’s interior or exterior. Work can be phased in. But it’s smart to make changes before rooms are decorated to avoid repainting.

Contractor Jeff Cohen, owner of Canada & Klein Ltd. in Winnetka, Ill., recommends starting with an electronic programmable thermostat that can be set to lower temperatures automatically, thereby saving heating costs. “It’s the quickest payback,” he says. Good models range between $50 and $250. But home owners should understand how to program it to save money, Amram says. Many buy it but don’t use it properly, she explains. New self-learning models like Nest make adjustments based on weather and how a house has performed historically.

Home owners should also use a high-quality caulk around windows and doors with poor seals, which is inexpensive but takes time. And it will need to be redone after several years, says Amram.

Some contractors also recommend applying film to glazing. The downside is that it may be visible and unattractive.

Installing door sweeps to close gaps is another good idea, as is plugging up light holes, switches, plumbing gaps, and other openings with a fire-resistant spray foam insulation or gaskets.

4. What about actual insulation?

Because hot air rises, home owners should start at the top of the house — with the atticif the residence has one. Unless they’re handy and can do it themselves, they should have a professional blow in fiberglass; cellulose (recycled newspapers ground up, which is very green); or spray foam, a mix of chemical compounds, but usually not as green an option. The type of insulation should depend in part on where the furnace is located and whether it needs replacement, since that may affect the ductwork. How much insulation is added should be according to R value recommendations.

Where it’s applied, on top of the floor or the underside of the roof deck, depends on the home’s design. In houses without an attic, the cavity between the roof and the bedrooms’ ceilings can be filled with insulation. Cellulose and spray foam offer the extra benefit of deterring pests; critters like fiberglass, however. As long as an attic’s being sealed, home owners should check that no openings allow cold or hot air through chimneys, walls, or the roof—perhaps from small creatures making holes, major “acts of God,” or simple wear and tear over time.

Next, home owners should focus on having a professional check walls. In cold climates, insulation can be added by cutting 3-inch holes into interior walls, blowing in cellulose, then covering the openings. It can also be applied on the exterior in colder areas and in retrofits where a professional removes siding, drills the 3-inch hole, plugs and seals it, and replaces the siding, Fischer says.

Adding insulation in a basement can be effective. Spray foam insulation, for instance, can be applied to the rim joist and where the house meets the foundation. Holes from electrical or plumbing work also should be filled. When a house sits on a concrete slab, Amram suggests wool rugs, sometimes with a layer underneath for warmth.

5. What if home owners have single-pane windows and can’t afford to replace them with insulated models?

Storm windows are a good line of defense, though some home owners don’t like how they alter a home’s exterior architectural integrity. A new thermal product called IndowWindows is an alternative that doesn’t affect the exterior since it sits inside a window frame, says Fischer. But home owners shouldn’t dismiss replacement windows right away since many buyers appreciate having them and they may make a house more comfortable. “They should do it for themselves and change those first with aluminum frames or leaks, or on the southwest side of a house in a hot part of the country,” Amram says.

6. Is there anything special home owners should do when adding on to a house?

Be sure their contractor installs insulation between old and new sections. “It’s often neglected,” Amram says.

7. Any final tips?

If home owners need to replace mechanical equipment, they should invest in the best energy-efficient models they can afford. Reduced energy consumption over time will help offset the price. Landscaping can also make a difference. A large leafy tree on a south-facing yard can cut sun entering a house and decrease air conditioning bills. Similarly, shrubs and foundation plantings reduce wind and air infiltration in winter, Fischer says.

The ultimate goal of insulating a home well is to create a continuous thermal barrier that’s within a home owner’s budget.